This invention relates to a method of preparing animal feeds and, more particularly, to a method employing disk pelletizing. Heretofore, and without exception, to my knowledge, animal feed pellets have been made in pellet mills, usually following some type of conditioning, i.e., cooking--see, for example, co-owned U.S. Pat. No. 4,001,451. The art has been specifically concerned with developing compacted or pressed pellets which have been deemed necessary to avoid the development of fines, dust, etc.
More particularly, the prior art procedures for making animal feed pellets have employed steam as a necessary means for effecting a chemical change of one kind or another in the mash or other starting material and before the same is introduced into the pellet mill. Such chemical reactions are characterized by gelatinization of plasticification which results in a change in the character of the particles.
According to the instant invention, however, I proceed in the directly opposite direction, employing not compaction but, rather agglomeration which results in a more rather than less porous product--as compared to the prior art. Even further, according to the discovered invention, I avoid the need for the chemical reactions normally encountered in the preparation of animal feeds which employ steam. In contrast to the prior art, the instant invention proceeds without change to the particle but merely employs a heretofore unappreciated advantageous build-up by disk pelletizing of one particle on another so as to provide an extremely useful animal feed under ordinary atmospheric conditions, i.e., in the absence of steam.
Disk pelletizing has been employed for many years, particularly in connection with agglomerating ore fines. The procedure involved introducing streams of dry and liquid material into a pan-like member rotating about an inclined axis which results in a "snow-balling" phenomenon wherein the particles agglomerate and thereafter spill over a side portion for collection and further processing.
To the best of my knowledge, this procedure has never been employed for animal feeds although subsequent to my invention, a search of the patent art revealed a mention of disk pelletizing in U.S. Pat. No. 3,464,824 relative to preparing animal feeds and U.S. Pat. No. 3,713,842 having to do with agglomerating ground coffee.
According to the limited disclosure available in the prior art patent '824, steam is essential during the agglomeration step. Further, the prior art '824 patent applies to a very limited group of starting materials to be used as ingredients of animal feeds. By the same token, the prior art '842 patent applies only to a specific material, i.e., coffee and then only when using instant coffee extract as the liquid additive in the disk pelletizer.
Quite surprising, compared with the limited teachings of the prior art, I have found that the invention is particularly effective when making the normal animal feed which has a multiplicity of components, i.e., normally at least 5 different elements or ingredients--of various characters, hardness, etc. In the practice of the invention, a multiple element mixture is introduced into the disk of a disk pelletizer simultaneous with the introduction of a liquid stream.
The resulting pellet, when dried to an equivalent moisture basis is characterized by a substantially reduced bulk density which provides a number of beneficial advantages as will be brought out hereinafter.
In one particularly advantageous facet of the invention, a milk replacer is provided through the agglomeration process. Milk replacer rations have been employed historically for two purposes: (1) for herd replacement, i.e., for raising calves without the presence of the mother cow, and (2) to raise white veal or Continental-style veal. Through the use of the invention, the milk replacer is characterized by an unexpectedly superior instantizing characteristic. Historically, milk replacers were reconstituted by water addition only after a prolonged period of at least 5 minutes accompanied by vigorous agitation. Milk replacer produced according to the instant invention can be reconstituted in less than a minute in the absence of any substantial stirring.
Other objects and advantages of the invention may be seen in the details of the ensuing specification.